Answer:
(x+5)/6
Explanation:
Let's assume the number is x. The sum of a number means addition so when you see "the sum of", it means addition. The things that are getting added are x and 5 so it becomes x+5. Then you divide x+5 by 6 and you get (x+5)/6
I added parentheses because I didn't know how to show the full fraction.